神农架川金丝猴栖息地乔木层物种多样性及其海拔梯度变化

应用样方调查法，分析了湖北神农架自然保护区川金丝猴栖息地植被乔木层物种多样性和群落结构随海拔梯度的变化。结果如下：（1）调查样方160个，总面积64000m^2，共记录木本植物37科123属289种，其中乔木25科90属198种，灌木7科29属84种，木质藤本5科4属7种。优势科主要有蔷薇科、忍冬科、樟科、壳斗科和杜鹃花科等。（2）根据不同海拔乔木层物种组成的差异，该区植被类型可分为落阔叶林（1900～2100m）、针阔叶混交林（2200～2400m）和暗针叶林（2500～2600m）3种。（3）随着海拔升高，多样性指数（Shannon—Wie—ner指数）在3种植被类型中旱下降趋势；均匀度指数（Pielou指数）在针阔叶混交林和暗针叶林中呈下降趋势，在落叶阔叶林中变化不明显。（4）随着海拔升高，各乔木层所占比例，乔木l层（〉20m）逐渐减小，乔木Ⅱ层（10～20m）无明显变化，乔木Ⅲ层（〈10m）呈上升趋势。（5）以树高替代年龄，分析了9种优势乔木村种的种群年龄结构，结果表明该区植被的乔木层呈现稳定增长趋势。

Species Diversity of the Tree Layer with Changes in Altitudes in Rhinopithecus roxellana Habitats at Shennongjia, China

Tree species diversity and community structure along the altitudinal gradient were analyzed through quadrat investigation at Rhinopithecus roxellana habitat of Shennongjia Nature Reserve. Major results include： （ 1 ） 289 woody species from 23 genera and 37 families were recorded in the 160 sampled plots, including 198 tree species from 90 genera and 25 families, 84 shrub species from 29 genera and 7 families and 7 liana species from 4 genera and 5 families. Rosaceae, Caprifoliaceae, Lauraceae, Fagaceae, and Ericaceae were the dominant families. （2） Based on the difference in tree species composition at different altitudes, vegetation of the study area was divided into Deciduous Broad-leaved Forest （1900 - 2100 m）, Coniferous and Broad-leaved Mixed Forest （2200 -2400 m）, and Dark Coniferous Forest （2500 -2600 m）. （3） The Shannon-Wiener index of the tree layers decreased with increasing elevation; the Pielou＇s index decreased with increasing elevation in the Coniferous and Broad-leaved Mixed Forest and the Dark Coniferous Forest, whereas showed no significant change in the Defoliate Broad-leaved Forest. （4） The proportion of the first tree layer （ 〉20 m） decreased as elevation rose, the proportion of the second tree layer （10 -20 m） showed no distinct change and the proportion of the third tree layer （ 〈10 m） increased. （5） As height of trees indicates age, the population age structure of nine dominant tree species showed that the tree layer had a steadily increasing trend in the study area.